JP6545300B2 - Electrolytic copper foil substantially free of wrinkles, electrode containing the same, secondary battery containing the same, and method of manufacturing the same - Google Patents

Description

  The present invention relates to an electrolytic copper foil substantially free of wrinkles, an electrode including the same, a secondary battery including the same, and a method of manufacturing the same.

  Electrolytic copper foils are used in the manufacture of various products such as cathodes for secondary batteries and flexible printed circuit boards (flexible printed circuit boards: FPCBs).

  When manufacturing electrolytic copper foils, it is not possible to avoid the wrinkles that typically occur in the manufacture of thin films unless the production conditions are precisely controlled.

  The electrolytic copper foil having wrinkles leads to a decrease in yield of the secondary battery and a decrease in quality of the secondary battery. Specifically, unevenness of the surface of the electrodeposited copper foil having wrinkles can not uniformly coat the cathode active material thereon. The non-uniform coating of the cathode active material causes a short circuit of the secondary battery or peeling of the cathode active material. Therefore, the wrinkles of the electrodeposited copper foil are one of the return events from the customer company.

  It is known to lower the weight deviation of the electrodeposited copper foil as part of an effort to control the wrinkling of the electrodeposited copper foil. However, in the case of an electrodeposited copper foil having a thickness of 8 μm or less, whose use ratio is increasing due to an increase in capacity of a secondary battery, wrinkles are produced despite the fact that the weight deviation is controlled very low. It still occurs.

  Accordingly, the present invention relates to an electrolytic copper foil, an electrode including the same, a secondary battery including the same, and a method of manufacturing the same, which can prevent the problems caused by the limitations and disadvantages of the related art as described above.

  One aspect of the present invention is to provide an electrolytic copper foil that is substantially free of wrinkles.

  Another aspect of the present invention is to provide an electrode capable of securing high productivity by being manufactured with an electrolytic copper foil substantially free of wrinkles.

  Yet another aspect of the present invention is to provide a secondary battery capable of securing high productivity by being manufactured with an electrolytic copper foil substantially free of wrinkles.

  Yet another aspect of the present invention is to provide a method of manufacturing an electrolytic copper foil capable of preventing wrinkles.

  In addition to the aspects of the invention described above, other features and advantages of the invention will be described hereinafter or will be apparent from such description to those skilled in the art to which the invention pertains. It should be

According to one aspect of the present invention as described above, an electrodeposited copper foil having a first surface and a second surface opposite to the first surface, the copper foil being directed to the matte surface and the second surface directed to the first surface. A copper layer including a shiny surface; a first protective layer on the matte surface; and a second protective layer on the shiny surface, each of the first and second surfaces being 4.8 to 16. 1 profile max ratio: have _{(profile max R a tio PMR)} , the profile max ratio (PMR) is the ratio of the maximum height roughness for the arithmetic average roughness _{(R a) (R max)} (R max / a R _a), wherein the electrolytic copper foil (220) plane texture coefficient 0.49~1.28 [TC (220)], the yield strength of 35~58kgf / mm ² and 3 And having the following weight variation, electrolytic copper foil is provided.

Each of the first and second surfaces may have a maximum height roughness (R _max ) of 1.2 to 3.7 μm and an arithmetic average roughness (R _a ) of 0.15 to 0.45 μm. .
The first and second protective layers may include chromium (Cr).

  The electrodeposited copper foil may have a thickness of 4 to 30 μm, preferably 4 to 8 μm.

According to another aspect of the present invention, there is provided an electrodeposited copper foil having a first surface and a second surface opposite to the first surface; and a first active material layer on the first surface, the electrodeposited copper foil having the first surface A copper layer including a matte side facing the surface and a shiny side facing the second side; a first protective layer on the matte side; and a second protective layer on the shiny side, each of the first and second sides Has a profile max ratio (PMR) of 4.8 to 16.1, which is the ratio (R _max ) of the maximum height roughness (R _max ) to the arithmetic mean roughness (R _a ) / R _a ), the electrodeposited copper foil has a (220) plane texture coefficient [TC (220)] of 0.49 to 1.28, a yield strength of 35 to 58 kgf / mm ² and a weight deviation of 3% or less Power source for a secondary battery, There is provided.

Each of the first and second surfaces may have a maximum height roughness (R _max ) of 1.2 to 3.7 μm and an arithmetic average roughness (R _a ) of 0.15 to 0.45 μm. .

  The first and second protective layers may include chromium (Cr).

  The electrodeposited copper foil may have a thickness of 4 to 30 μm, preferably 4 to 8 μm.

  The electrode for the secondary battery may further include a second active material layer on the second surface, and the first and second active material layers may be, independently of each other, carbon; Si, Ge, Sn, Li A metal of Zn, Mg, Cd, Ce, Ni or Fe; an alloy containing the metal; an oxide of the metal; and one or more active materials selected from the group consisting of the metal and the carbon complex Can be included.

  According to still another aspect of the present invention, an anode; a cathode comprising the electrode for a secondary battery; an electrolyte providing an environment in which lithium ions can move between the anode and the cathode; A secondary battery is provided, comprising: a separator electrically insulating the anode and the cathode.

According to still another aspect of the present invention, the method includes the steps of: forming a copper layer; and forming a protective layer on the copper layer, wherein the copper layer forming step includes 70 to 90 g / L of copper ions, 50 to 150 g / L sulfuric acid, 2-20 mg / L N-allylthiourea (N-allylthiourea: ATU), and 2-20 mg / L bis (3-sulfopropyl) disulfide [bis- (3-sulfopropyl) disulfide: SPS] prepare the electrolyte solution comprises; and the step of performing electroplating by energizing the electrolyte electrode plate and the rotary electrode drum disposed spaced apart from each other in a current density of 40 to 80 a / dm ² The surface of the rotating electrode drum is polished with a brush having a grain size (Grit) of # 800 to # 3000; The electrolytic copper foil manufacturing method is provided, wherein the silver (Ag) concentration in the electrolyte is maintained at 50 mg / L or less during electroplating.

  The preparing of the electrolyte comprises heat treating the copper wire at 600 to 900 ° C. for 30 to 60 minutes; pickling the heat treated copper wire; charging the pickled copper wire to sulfuric acid; And adding the N-allylthiourea (ATU) and bis (3-sulfopropyl) disulfide (SPS) to the sulfuric acid charged with the copper wire.

Continuous filtration may be performed on the electrolyte while the electroplating is performed, and the flow rate of the electrolyte may be 39 to 46 m ³ / hr when the continuous filtration is performed.

  The deviation of the flow rate may be 5% / sec or less while the electroplating is performed.

  The copper layer forming step may include electrolysis of chloride ions capable of precipitating silver (Ag) in the form of AgCl in order to prevent the concentration of silver (Ag) in the electrolyte solution from exceeding 50 mg / L. The method may further comprise the step of adding to the solution.

  The forming of the protective layer may include immersing the copper layer in an anticorrosive solution containing 0.5 to 1.5 g / L of Cr.

  The foregoing general description of the present invention is only for illustrating or explaining the present invention and does not limit the scope of the present invention.

  According to the present invention, an electrolytic copper foil substantially free of wrinkles can be manufactured, and as a result, the cathode active material can be uniformly coated on the electrolytic copper foil when manufacturing the secondary battery cathode. Therefore, according to the present invention, the short circuit of the secondary battery and the exfoliation of the cathode active material due to the nonuniform coating of the cathode active material can be prevented. That is, according to the present invention, the life and capacity retention rate of the secondary battery can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to aid in the understanding of the present invention and to constitute a part of this specification, and illustrate the embodiments of the present invention and explain the principles of the present invention together with the detailed description of the invention.
FIG. 2 is a cross-sectional view of a secondary battery electrode according to an embodiment of the present invention. It is the drawing which illustrated the XRD graph of the electrolytic copper foil. It is a photograph of the electrolytic copper foil of the comparative example 1 which the wrinkles generate | occur | produced. It is a photograph of the electrolytic copper foil of Comparative Example 4 broken in the manufacturing process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible without departing from the technical spirit and scope of the present invention. Accordingly, the present invention includes all modifications and variations that fall within the scope of the claimed invention and equivalents thereof.

  A lithium ion secondary battery includes an anode, a cathode, an electrolyte that provides an environment in which lithium ions can move between the anode and the cathode, and electrons generated at one electrode are the secondary battery. And a separator that electrically insulates the anode and the cathode to prevent them from being wasted by moving to the other electrode through the inside of the.

  FIG. 1 is a cross-sectional view of a secondary battery electrode according to an embodiment of the present invention.

  As illustrated in FIG. 1, an electrode 100 for a secondary battery according to an embodiment of the present invention includes an electrodeposited copper foil 110 having a first surface S1 and a second surface S2 opposite to the first surface S1. And a second active material layer 120b on the second surface S2. FIG. 1 shows an example in which active material layers 120a and 120b are respectively formed on all of the first and second surfaces S1 and S2 of the electrodeposited copper foil 110, but the present invention is not limited thereto. The electrode 100 for a secondary battery of the present invention may include only one of the first and second active material layers 120a and 120b as an active material layer.

  In a lithium secondary battery, an aluminum foil is used as an anode current collector to be combined with an anode active material, and as a cathode current collector to be combined with an anode active material. Generally, electrolytic copper foil is used.

  According to an embodiment of the present invention, the secondary battery electrode 100 is used as a cathode of a lithium secondary battery, and the electrodeposited copper foil 110 functions as a cathode current collector, and the first and second active material layers are used. 120a and 120b contain a cathode active material.

  As illustrated in FIG. 1, the electrodeposited copper foil 110 of the present invention has a copper layer 111 including a matte surface MS and a shiny surface SS, and a copper layer 111 on the matte surface MS of the copper layer 111. And a second protective layer 112 b on the shiny side SS of the copper layer 111.

  The matte surface MS is a surface of the copper layer 111 directed to the first surface S 1 of the electrodeposited copper foil 110, and the shiny surface SS is a surface of the copper layer 111 directed to the second surface S 2 of the electrodeposited copper foil 110.

  The copper layer 111 of the present invention may be formed on the rotary electrode drum through electroplating, but the shiny surface SS indicates a surface in contact with the rotary electrode drum in the electroplating process, and the matte surface MS is the shiny surface SS. Point to the opposite side of the

Although the shiny surface SS generally has a lower 10-point average roughness (R _z ) compared to the matte surface MS, the present invention is not limited thereto, and the 10-point average roughness of the shiny surface SS ( R _z) may be higher still if it were the same as the 10-point average roughness of the matte surface MS _{(R z).}

  The first and second protective layers 112a and 112b prevent corrosion of the copper layer 111 to improve heat resistance, and may include chromium (Cr).

According to an embodiment of the present invention, the chromium (Cr) deposition on each of the first and second surfaces S1 and S2 may be 1 to 5 mg / m ² .

  As described above, the wrinkled electrolytic copper foil 110 causes non-uniform coating of the cathode active material, and non-uniform coating of the cathode active material causes shorting of the secondary battery and peeling of the cathode active material. Therefore, the electrolytic copper foil 110 must be manufactured in consideration of all factors that cause the electrolytic copper foil 110 to wrinkle.

  According to the present invention, we have identified the fact that factors such as surface profile of the electrodeposited copper foil 110, crystal structure of the surface, yield strength, weight deviation etc cause wrinkles of the electrodeposited copper foil 110. Therefore, in order to minimize the wrinkles of the electrodeposited copper foil 110, it is necessary to precisely control the important factor.

The surface profile closely related to the grain size can be represented by arithmetic mean roughness (R _a ) and maximum height roughness (R _max ), and the crystal structure of the surface has a (220) surface texture coefficient [TC (220)] can be represented.

According to the present invention, in order to minimize wrinkling of the electrolytic copper foil 110, the first and second surfaces S1, S2 each profile Max ratio of _{4.8~16.1 (Profile Max R a tio:} PMR And the electrodeposited copper foil has a (220) surface texture coefficient [TC (220)] of 0.49 to 1.28, a yield strength of 35 to 58 kgf / mm ² , and a weight deviation of 3% or less Have.

The profile max ratio (PMR) means the ratio (R _max / R _a ) of the maximum height roughness (R _max ) to the arithmetic mean roughness (R _a ). In the present invention, the arithmetic mean roughness (R _a ) and the maximum height roughness (R _max ) are measured in accordance with JIS B 0601-2001 standard [measurement length: 4 mm (cut off section excluded)] .

  If the profile max ratio (PMR) exceeds 16.1, air may be trapped between the electrodeposited copper foil 110 and the electrodeposited copper foil 110 when the electrodeposited copper foil 110 manufactured through electrolytic plating is wound on a bobbin. This causes wrinkles. On the other hand, the electrodeposited copper foil 110 is locally stretched when the electrodeposited copper foil 110 is wound on a roll for a roll-to-roll (RTR) process if the profile max ratio (PMR) is less than 4.8. And wrinkles occur.

According to an embodiment of the present invention, each of the first and second surfaces S1, S2 has a maximum height roughness (R _max ) of 1.2 to 3.7 μm and an arithmetic average of 0.15 to 0.45 μm. It can have _a roughness (R _a ).

  In the present invention, the (220) surface texture coefficient [TC (220)] is measured and calculated as follows.

First, perform X-ray diffraction (XRD) [Target: Copper K alpha 1, 2θ interval: 0.01 °, 2θ scan speed: 3 ° / min] in the range of diffraction angles (2θ) of 30 ° to 95 °. According to the above, an XRD graph having peaks corresponding to n crystal planes [e.g., as illustrated in FIG. 2, it corresponds to (111) plane, (200) plane, (220) plane, and (311) plane] An XRD graph in which a peak appears] is obtained, and the XRD diffraction intensity [I (hkl)] of each crystal plane (hkl) is obtained from this graph. In addition, the XRD diffraction intensity [I ₀ (hkl)] for each of the n crystal planes of the standard copper powder defined by JCPDS (Joint Committee on Powder Diffraction Standards) is determined. Subsequently, the division after obtaining the arithmetic mean value, at the arithmetic average value (220) plane of the I ₍₂₂₀₎ / I 0 (220) of said n crystal plane _{I (hkl) / I 0 (} hkl) The (220) surface texture coefficient [TC (220)] is calculated by That is, the (220) plane aggregation texture coefficient [TC (220)] is calculated based on the following equation 1.

  When the (220) plane texture coefficient [TC (220)] is less than 0.49, the crystal structure of the electrodeposited copper foil 110 is not dense, so the crystal structure is easily formed when the electrodeposited copper foil 110 is wound on a bobbin. It is deformed and causes wrinkles. On the other hand, when the (220) plane texture coefficient [TC (220)] exceeds 1.28, the crystal structure of the electrodeposited copper foil 110 is excessively dense, so that it has strong brittleness, As a result, the electrolytic copper foil 110 is broken in the manufacturing process.

  In the present invention, the above-mentioned yield strength is the yield strength measured at a normal temperature of 25 ° C. and measured with a universal tester (UTM) (width of sample: 12.7 mm, distance between Grips: 50 mm, measurement speed: 50 mm / min).

If the yield strength of the electrodeposited copper foil 110 is less than 35 kgf / mm ² , plasticity deformation is caused when winding the electrodeposited copper foil 110 on a bobbin, and the wrinkles are accelerated. On the other hand, if the yield strength of the electrodeposited copper foil 110 exceeds 58 kgf / mm ² , the brittleness of the electrodeposited copper foil 110 becomes strong and not only the compatibility (compatability) decreases, but also the electrodeposited copper foil 110 is broken Becomes larger.

  In the present invention, the weight deviation means a weight deviation in the width direction, which is measured and calculated as follows.

  After taking samples of 5 cm × 5 cm in size from the left side point, the center point, and the right side point located along the width direction of the electrodeposited copper foil 110, the weights of the three samples are measured respectively. After the arithmetic mean weight and the standard deviation are determined using the measured values, the ratio (%) of the standard deviation to the arithmetic mean weight [ie, (standard deviation / arithmetic mean weight) × 100] is calculated.

  When the weight deviation of the electrodeposited copper foil 110 exceeds 3%, when the electrodeposited copper foil 110 is wound on a bobbin, the electrodeposited copper foil 110 is locally stretched and wrinkles occur.

  The electrodeposited copper foil 110 of the present invention can have a stretching ratio of 3% or more at normal temperature (25 ° C.). If the stretching ratio of the electrodeposited copper foil 110 is less than 3%, the force applied in the manufacturing process of the electrodeposited copper foil 110 or the manufacturing process of the secondary battery electrode 100 increases the risk of the electrodeposited copper foil 110 breaking without elongation. .

  The electrodeposited copper foil 110 of the present invention can have a thickness of 4 to 30 μm, preferably 4 to 8 μm. When the thickness of the electrodeposited copper foil 110 is less than 4 μm, the workability in the manufacturing process of the secondary battery is reduced. On the other hand, when the thickness of the electrodeposited copper foil 110 exceeds 30 μm, the capacity of a preferable secondary battery can not be secured.

  In particular, the electrolytic copper foil 110 having a thickness of 8 μm or less, which is in increasing demand for the production of a high capacity secondary battery, is difficult to prevent wrinkles only by lowering the weight deviation. Further technical features need to be applied.

  The first and second active material layers 120a and 120b are, independently of each other, a metal of carbon; Si, Ge, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; an alloy containing the metal; The cathode active material can include one or more active materials selected from the group consisting of metal oxides; and complexes of the metals and carbon.

  In order to increase the charge and discharge capacity of the secondary battery, the first and second active material layers 120a and 120b may be formed of a mixture containing a predetermined amount of Si.

  Hereinafter, a method of manufacturing the electrodeposited copper foil 110 according to an embodiment of the present invention will be specifically described.

  The method of the present invention includes the steps of forming a copper layer 111 and forming protective layers 112a, 112b on the copper layer 111.

  First, 70-90 g / L of copper ion, 50-150 g / L of sulfuric acid, 2-20 mg / L of N-allylthiourea (N-allylthiourea: ATU), and 2-20 mg / L of bis (3-sulfopropyl) 2.) Prepare an electrolyte containing disulfide [bis- (3-sulfopropyl) disulfide (SPS)].

  The yield strength of the electrodeposited copper foil 110 can be controlled by adjusting the concentration of the N-allylthiourea (ATU). As the concentration of the N-allylthiourea (ATU) increases, the yield strength of the electrodeposited copper foil 110 generally increases.

  By controlling the concentration of the bis (3-sulfopropyl) disulfide (SPS), the (220) surface texture coefficient [TC (220)] of the first and second surfaces S1 and S2 of the electrodeposited copper foil 110 is controlled. can do. As the concentration of bis (3-sulfopropyl) disulfide (SPS) increases, the (220) surface texture coefficient [TC (220)] of the electrodeposited copper foil 110 generally increases.

  The electrolytic solution heats the high purity copper wire at 600 to 900 ° C. for 30 to 60 minutes to bake the organic matter, picks the heat treated copper wire, and feeds the pickled copper wire to sulfuric acid. The electrolyte may be prepared by adding N-allylthiourea (ATU) and bis (3-sulfopropyl) disulfide (SPS) to the electrolyte after preparing the electrolyte with little or no impurities.

Subsequently, the copper is electroplated by applying an electric current density of 40 to 80 A / dm ² between the electrode plate and the rotating electrode drum which are disposed apart from each other in the electrolytic solution at 50 to 60 ° C. A layer 111 is formed on the rotary electrode drum.

The current density affects the arithmetic mean roughness (R _a ) of the electrodeposited copper foil 110. The higher the current density, the lower the arithmetic mean roughness (R _a ). In other words, the lower the current density, the higher the arithmetic mean roughness (R _a ).

  The surface of the rotating electrode drum (the surface on which copper is deposited by electroplating) is polished with a polishing brush having a particle size (Grit) of # 800 to # 3000. It is preferable that the surface of the rotating electrode drum is uniformly polished in the width direction by performing polishing while spraying water in the width direction of the surface of the rotating electrode drum.

The degree of polishing of the surface of the rotating electrode drum (the surface on which copper is deposited by electroplating) is the arithmetic mean roughness (R _a ) of the second surface S2 of the electrodeposited copper foil 110, the maximum height roughness (R _max ), etc. Affect

According to the present invention, the silver (Ag) concentration in the electrolyte is maintained at 50 mg / L or less while the electroplating is performed. The silver (Ag) concentration affects the maximum height roughness (R _max ) of the electrodeposited copper foil 110. As the silver (Ag) concentration is lower, the maximum height roughness (R _max ) of the electrodeposited copper foil 110 is generally increased.

  In order to prevent silver (Ag) from flowing into the electrolyte and causing the concentration of silver (Ag) in the electrolyte to exceed 50 mg / L when the electroplating is performed, silver (Ag) of AgCl is used. A small amount (eg, 15 to 25 mg / L) of chloride ions that can be precipitated in the form can be added to the electrolyte. As a result, the electrolytic solution can have, for example, a silver concentration of 1 to 50 mg / L.

Continuous (or circulation) filtration for removing solid impurities from the electrolyte may be performed at a flow rate of 39 to 46 m ³ / hr while the electroplating is performed. If the flow rate is less than 39 m ³ / hr, the flow rate is lowered to increase the overvoltage, and the copper layer 111 is formed unevenly. On the other hand, when the flow rate exceeds 46 m ³ / hr, damage to the filter is induced and foreign matter flows into the electrolyte. The flow velocity of the electrolyte also affects the yield strength of the electrodeposited copper foil 110.

  In order to manufacture the electrodeposited copper foil 110 having a weight deviation of 3% or less, it is preferable to control the deviation of the flow rate to 5% / sec or less while the electroplating is performed. When the deviation of the flow velocity of the electrolyte exceeds 5% / sec, the deviation of the efficiency of copper plating increases along the width direction of the copper layer 111 so that the weight deviation of the electrodeposited copper foil 110 exceeds 3%. Become.

  The copper layer 111 produced as described above is immersed in an antirust solution containing 0.5 to 1.5 g / L of Cr (for example, at normal temperature for 2 to 20 seconds) and then dried. First and second protective layers 112a and 112b are formed on the copper layer 111, respectively.

  The anticorrosion solution may further contain at least one or more of a silane compound and a nitrogen compound. For example, the anticorrosion solution can contain 0.5 to 1.5 g / L of Cr and 0.5 to 1.5 g / L of a silane compound.

  By coating the cathode active material on the thus-produced electrolytic copper foil 110 of the present invention, the secondary battery electrode (i.e., cathode) of the present invention can be manufactured.

  The cathode active material is a metal of carbon; Si, Ge, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; an alloy containing the metal; an oxide of the metal; and a composite of the metal and carbon It may be selected from the group consisting of

For example, after mixing 100 parts by weight of carbon for a cathode active material with 1 to 3 parts by weight of styrene butadiene rubber (SBR) and 1 to 3 parts by weight of carboxymethylcellulose (CMC), a slurry using distilled water as a solvent Prepare. Subsequently, the slurry is applied to a thickness of 20 to 100 μm on the electrodeposited copper foil 110 using a doctor blade and pressed at 110 to 130 ° C. under a pressure of 0.5 to 1.5 ton / cm ² .

  A lithium secondary battery can be manufactured using a common anode, an electrolyte, and a separation membrane together with the electrode (cathode) for a secondary battery of the present invention manufactured by the above method.

  Hereinafter, the present invention will be specifically described through examples and comparative examples. However, the following examples are only for the purpose of assisting the understanding of the present invention, and the scope of the present invention is not limited to these examples.

Example 1-6 and Comparative Example 1-7
A copper layer was formed on the rotating electrode drum by energizing the electrode plate and the rotating electrode drum arranged to be separated from each other in the electrolytic solution at a current density of 60 A / dm ² . The electrolyte contained 75 g / L copper ion, 100 g / L sulfuric acid, N-allylthiourea (ATU), and bis (3-sulfopropyl) disulfide (SPS) and was maintained at 55 ° C. The flow rate of the electrolyte was 42 m ³ / hr. The ATU concentration, the SPS concentration, the silver (Ag) concentration, the deviation of the flow velocity of the electrolyte, and the particle size of the polishing brush used for polishing the surface of the rotary electrode drum are as shown in Table 1 below. An electrolytic copper foil was completed by immersing the copper layer formed through the electroplating in an anticorrosive solution and then drying it.

  The profile max ratio (PMR), the (220) surface texture coefficient [TC (220)], the yield strength, and the weight deviation of the electrodeposited copper foils of the example and the comparative example manufactured as described above are as follows. The results are shown in Table 2 below. Further, Table 2 shows the presence or absence of the occurrence of wrinkles or rupture in the manufacturing process of the electrodeposited copper foils of Examples and Comparative Examples.

* Profile Max Ratio (PMR)
A Mitutoyo SJ-310 roughness tester is used for each of the first surface (surface adjacent to the matte surface of the copper layer) and the second surface (surface adjacent to the shiny surface of the copper layer) of the electrolytic copper foil. Arithmetic mean roughness (R _a ) and maximum height roughness (R _max ) were measured in accordance with the JIS B 0601-2001 standard [measurement length: 4 mm (cut off section excluded)]. Subsequently, the arithmetic mean roughness maximum height roughness for _{(R a)} the ratio of _{(R max) (R max /} R a) each profile Max ratio of the first and second surface by calculating the (PMR) I asked for.

* (220) face organization coefficient [TC (220)]
X-ray diffraction method (XRD) [(i) Target: Copper K alpha 1, (ii) 2θ interval: 0.01 °, (iii) 2θ scan speed: 3 ° / in a diffraction angle (2θ) range of 30 ° to 95 ° min] to obtain an XRD graph having peaks corresponding to n crystal planes, and the XRD diffraction intensity [I (hkl)] of each crystal plane (hkl) was determined from this graph. In addition, XRD diffraction intensities [I ₀ (hkl)] were determined for each of the n crystal planes of a standard copper powder defined by JCPDS (Joint Committee on Powder Diffraction Standards). Subsequently, the division after obtaining the arithmetic mean value, at the arithmetic average value (220) plane of the I ₍₂₂₀₎ / I 0 (220) of said n crystal plane _{I (hkl) / I 0 (} hkl) By doing this, the (220) plane texture coefficient [TC (220)] of the electrodeposited copper foil 110 was calculated. That is, the (220) plane aggregation texture coefficient [TC (220)] was calculated based on the following equation 1.

* Yield strength (kgf / mm ² )
The yield strength of the electrodeposited copper foil was measured with a universal tester (UTM) at a room temperature of 25 ° C. The width of the sample was 12.7 mm, the distance between Grips was 50 mm, and the measurement speed was 50 mm / min.

* Weight deviation (%)
The weight of each of the three samples was measured after taking samples of 5 cm × 5 cm in size from the left side point, the center point, and the right side point located side by side along the width direction of the electrodeposited copper foil. After the arithmetic mean weight and the standard deviation were determined using the measured values, the ratio (%) of the standard deviation to the arithmetic mean weight [ie, (standard deviation / arithmetic mean weight) × 100] was calculated.

As can be seen from Table 2 above, when the electrodeposited copper foil includes a surface having a profile max ratio (PMR) of less than 4.8 (comparative example 1), the electroplated copper foil has a profile max ratio (PMR greater than 16.1). When the electrolytic copper foil has a (220) surface texture coefficient [TC (220)] of less than 0.49 (comparative example 6), the electrolytic copper foil has 35 kgf / (comparative example 2) Wrinkles occurred in the process of producing the electrodeposited copper foil when the yield strength was less than ² mm ² (Comparative Example 3) and when the electrodeposited copper foil had a weight deviation of more than 3% (Comparative Example 5). FIG. 3 is a photograph of the electrodeposited copper foil of Comparative Example 1 in which wrinkles occurred.

In addition, when the electrolytic copper foil had a yield strength exceeding 58 kgf / mm ² (Comparative Example 4), the electrolytic copper foil ruptured. FIG. 4 is a photograph of the electrolytic copper foil of Comparative Example 4 broken in the manufacturing process.

  In particular, in the case where the electrodeposited copper foil had a (220) surface texture coefficient [TC (220)] exceeding 1.28 (Comparative Example 7), all wrinkles and rupture occurred.

100: Electrode for secondary battery 110: Electrodeposited copper foil 111: Copper layer 112a: first protective layer 112b: second protective layer 120a: first active material layer 120b: second active material layer

Claims (14)

In an electrolytic copper foil having a first surface and a second surface opposite to the first surface,
A copper layer comprising a matte surface towards said first surface and a shiny surface towards said second surface;
A first protective layer on the matte side; and a second protective layer on the shiny side,
Wherein the first and the second surface each profile Max ratio of _{4.8~16.1 (Profile Max R a tio:} PMR) has the profile Max Ratio (PMR) is an arithmetic mean roughness _(R a) Ratio of maximum height roughness (R _max ) to (R _max / R _a ),
Each of the first and second surfaces has a maximum height roughness (R _max ) of 1.2 to 3.7 μm and an arithmetic average roughness (R _a ) of 0.15 to 0.45 μm,
The electrodeposited copper foil is characterized by having a (220) plane texture coefficient [TC (220)] of 0.49 to 1.28, a yield strength of 35 to 58 kgf / mm ² and a weight deviation of 3% or less. , Electrolytic copper foil.   The electrodeposited copper foil of claim 1, wherein the first and second protective layers comprise chromium (Cr).   The electrodeposited copper foil according to claim 1, wherein the electrodeposited copper foil has a thickness of 4 to 30 μm. An electrodeposited copper foil having a first surface and an opposite second surface; and a first active material layer on the first surface,
The electrodeposited copper foil is
A copper layer including a matte side towards said first side and a shiny side towards said second side;
A first protective layer on the matte side; and a second protective layer on the shiny side,
Each of the first and second surfaces has a profile max ratio (PMR) of 4.8 to 16.1, and the profile max ratio (PMR) is the maximum height roughness to the arithmetic mean roughness (R _a ) (R _max ) ratio (R _max / R _a ),
Each of the first and second surfaces has a maximum height roughness (R _max ) of 1.2 to 3.7 μm and an arithmetic average roughness (R _a ) of 0.15 to 0.45 μm,
The electrodeposited copper foil is characterized by having a (220) plane texture coefficient [TC (220)] of 0.49 to 1.28, a yield strength of 35 to 58 kgf / mm ² and a weight deviation of 3% or less. , Electrode for secondary battery. The electrode for a secondary battery according to claim 4 , wherein the first and second protective layers contain chromium (Cr). The electrode for a secondary battery according to claim 4 , wherein the electrodeposited copper foil has a thickness of 4 to 30 μm. Further comprising a second active material layer on the second surface,
The first and second active material layers are, independently of one another, a metal of carbon; Si, Ge, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; an alloy containing the metal; oxidation of the metal The electrode for a secondary battery according to claim 4 , further comprising one or more active materials selected from the group consisting of: metal; and a complex of the metal and carbon. Anode (cathode);
A cathode (anode) comprising the electrode for a secondary battery according to any one of claims 4 to 7 ;
A secondary battery comprising: an electrolyte which provides an environment in which lithium ions can move between the anode and the cathode; and a separator which electrically insulates the anode and the cathode. Forming a copper layer; and forming a protective layer on the copper layer,
In the copper layer forming step,
70-90 g / L copper ion, 50-150 g / L sulfuric acid, 2-20 mg / L N-allylthiourea (ATU), and 2-20 mg / L bis (3-sulfopropyl) disulfide Preparing an electrolyte comprising [bis- (3-sulfopropyl) disulfide: SPS]; and a current density of 40-80 A / dm ² between an electrode plate and a rotating electrode drum arranged apart from each other in the electrolyte. Performing the electroplating by energizing at
The surface of the rotating electrode drum is polished with a brush having a grain size (Grit) of # 800 to # 3000,
A method of producing an electrodeposited copper foil, wherein the silver (Ag) concentration in the electrolytic solution is maintained at 50 mg / L or less while the electroplating is performed. In the electrolyte preparation step,
Heat treating the copper wire at 600-900 ° C. for 30-60 minutes;
Pickling the heat-treated copper wire;
Charging the acid-washed copper wire into sulfuric acid; and adding N-allylthiourea (ATU) and bis (3-sulfopropyl) disulfide (SPS) to the sulfuric acid charged with the copper wire. The electrolytic copper foil manufacturing method of Claim 9 characterized by the above-mentioned. Continuous filtration on the electrolyte is performed while the electroplating is performed,
The flow velocity of the electrolytic solution, characterized in that a 39~46m 3 / ^hr, an electrolytic copper foil production method of claim 9 when the continuous filtration is performed. The method of claim 11 , wherein the deviation of the flow rate is 5% / sec or less while the electroplating is performed. In the copper layer forming step,
In order to prevent the concentration of silver (Ag) in the electrolyte solution from exceeding 50 mg / L, adding chloride ion capable of precipitating silver (Ag) in the form of AgCl to the electrolyte solution is further added. The electrolytic copper foil manufacturing method of Claim 9 characterized by including. The method according to claim 9 , wherein the step of forming the protective layer includes the step of immersing the copper layer in an anticorrosive solution containing 0.5 to 1.5 g / L of Cr. .